By the Grace of G‑d
27 Shevat, 5724 [February 10, 1964]
Brooklyn, N.Y.

Greeting and Blessing:

I received your note in which you write about your son. If you will let me know your son's full Hebrew name as well as your full Hebrew name, I will remember him in prayer for a speedy recovery.

I trust you will not take the following remarks amiss, but I consider it my duty to mention that very often this kind of disorder in children is due to the fact that the parents have not observed Taharas HaMishpacha at the time of conception. If, G‑d forbid, this was the case it is necessary to bear in mind that Teshuva (repentance, return) is effective also retroactively to a considerable extent, so that it is possible to rectify the failure of the past. This means that you and your husband should, from now on, resolve firmly to observe the laws of Taharas HaMishpacha, and should try to impress your friends with the vital importance of observing these laws...

(Excerpt from a letter)